1. Field of the Invention
The present invention relates to an image forming apparatus and a power supply control method performed in the image forming apparatus.
2. Description of the Related Art
In recent years, image forming apparatuses such as printers have become common that can be driven not only by supply of power from a commercial power supply outside of an apparatus body via an AC adapter, but also by supply of power from a battery removably installed in the apparatus body.
To reduce power consumption as much as possible, the image forming apparatuses have a power-saving mode in which power supply is small until a print command is received while a print operation is stopped. A switching time is preset from when the print operation is finished in the normal mode allowing image formation until the mode changes to the power-saving mode, and a user can freely change the preset switching time.
In general, so as to prevent defective ejection of ink due to drying of nozzles, an inkjet printer performs maintenance operations for the nozzles after a print head has stood by for printing without being driven for a preset time or longer.
Japanese Laid-open Patent Publication No. 2009-222824 discloses a technology in which the mode is switchable between the power-saving mode and the normal mode, and a power source is supplied by using a secondary battery in accordance with the switched mode (operating state).
Japanese Laid-open Patent Publication No. 2012-140003 discloses a technology in which a head maintenance condition varies between when power is supplied from a commercial power supply and when an inkjet printer is driven by a battery, in order to extend the duration of the battery.
In an image forming apparatus disclosed in Japanese Laid-open Patent Publication No. 2009-222824 that can be driven by a battery, however, the switching time to the power-saving mode is set to the same value both while the image forming apparatus is driven by the commercial power supply and while the apparatus is driven by the battery. This causes a problem in that the user needs to manually reset the preset switching time to the power-saving mode to a shorter time so as to reduce the power consumption when the image forming apparatus is driven by the battery.
The inkjet printer disclosed in Japanese Laid-open Patent Publication No. 2012-140003 performs the maintenance operations for the nozzles when the inkjet printer is driven by the battery at the same frequency as when the printer is driven by the commercial power supply. This causes a problem in that the power consumption cannot be reduced when the inkjet printer is driven by the battery.
Therefore, there is a need to provide an image forming apparatus and a power supply control method that are capable of reducing the power consumption when the apparatus is driven by an auxiliary power supply.